Ablation devices with adjustable radiating section lengths, electrosurgical systems including same, and methods of adjusting ablation fields using same

ABSTRACT

An energy applicator for directing energy to tissue includes a feedline and a radiating section operably coupled to the feedline, wherein the radiating section has a length. The energy applicator also includes a length adjustment member adapted to allow for selective adjustment of the length of the radiating section.

BACKGROUND

1. Technical Field

The present disclosure relates to electrosurgical devices suitable foruse in tissue ablation applications and, more particularly, to ablationdevices with adjustable radiating section lengths, electrosurgicalsystems including the same, and methods of adjusting ablation fieldsusing the same.

2. Discussion of Related Art

Treatment of certain diseases requires the destruction of malignanttissue growths, e.g., tumors. Electromagnetic radiation can be used toheat and destroy tumor cells. Treatment may involve inserting ablationprobes into tissues where cancerous tumors have been identified. Oncethe probes are positioned, electromagnetic energy is passed through theprobes into surrounding tissue.

In the treatment of diseases such as cancer, certain types of tumorcells have been found to denature at elevated temperatures that areslightly lower than temperatures normally injurious to healthy cells.Known treatment methods, such as hyperthermia therapy, heat diseasedcells to temperatures above 41° C. while maintaining adjacent healthycells below the temperature at which irreversible cell destructionoccurs. These methods involve applying electromagnetic radiation toheat, ablate and/or coagulate tissue. Microwave energy is sometimesutilized to perform these methods. Other procedures utilizingelectromagnetic radiation to heat tissue also include coagulation,cutting and/or ablation of tissue.

Electrosurgical devices utilizing electromagnetic radiation have beendeveloped for a variety of uses and applications. A number of devicesare available that can be used to provide high bursts of energy forshort periods of time to achieve cutting and coagulative effects onvarious tissues. There are a number of different types of apparatus thatcan be used to perform ablation procedures. Typically, microwaveapparatus for use in ablation procedures include a microwave generatorthat functions as an energy source, and a microwave surgical instrument(e.g., microwave ablation probe) having an antenna assembly fordirecting the energy to the target tissue. The microwave generator andsurgical instrument are typically operatively coupled by a cableassembly having a plurality of conductors for transmitting microwaveenergy from the generator to the instrument, and for communicatingcontrol, feedback and identification signals between the instrument andthe generator.

There are several types of microwave probes in use, e.g., monopole,dipole and helical, which may be used in tissue ablation applications.In monopole and dipole antenna assemblies, microwave energy generallyradiates perpendicularly away from the axis of the conductor. Monopoleantenna assemblies typically include a single, elongated conductor. Atypical dipole antenna assembly includes two elongated conductors thatare linearly aligned and positioned end-to-end relative to one anotherwith an electrical insulator placed therebetween. Helical antennaassemblies include helically-shaped conductor configurations of variousdimensions, e.g., diameter and length. The main modes of operation of ahelical antenna assembly are normal mode (broadside), in which the fieldradiated by the helix is maximum in a perpendicular plane to the helixaxis, and axial mode (end fire), in which maximum radiation is along thehelix axis.

A microwave transmission line typically includes a long, thin innerconductor that extends along the longitudinal axis of the transmissionline and is surrounded by a dielectric material and is furthersurrounded by an outer conductor around the dielectric material suchthat the outer conductor also extends along the transmission line axis.In one variation of an antenna, a waveguiding structure, such as alength of transmission line or coaxial cable, is provided with aplurality of openings through which energy “leaks” or radiates away fromthe guiding structure. This type of construction is typically referredto as a “leaky coaxial” or “leaky wave” antenna.

During certain procedures, it can be difficult to assess the extent towhich the microwave energy will radiate into the surrounding tissue,making it difficult to determine the area or volume of surroundingtissue that will be ablated. Ablation volume is correlated with antennadesign, antenna performance, antenna impedance, ablation time andwattage, and tissue characteristics, e.g., tissue impedance. Theparticular type of tissue ablation procedure may dictate a particularablation volume in order to achieve a desired surgical outcome. By wayof example and without limitation, a spinal ablation procedure may callfor a longer, narrower ablation volume, whereas in a prostate ablationprocedure a more spherical ablation volume may be required. Treatment ofcertain tumors may involve probe repositioning during the ablationprocedure, such as where the tumor is larger than the probe or has ashape that does not correspond with available probe geometry orradiation pattern.

Ablation procedures may be improved by avoiding inadvertent applicationof ablative energy to tissue structures, such as large vessels, healthyorgans, sensitive neural structures, or vital membrane barriers. Tissueablation devices capable of influencing ablation volume may enable moreprecise ablation treatments, which may lead to shorter patient recoverytimes, fewer complications from undesired tissue damage, and improvedpatient outcomes.

SUMMARY

The present disclosure relates to an energy applicator for directingenergy to tissue including a feedline and a radiating section operablycoupled to the feedline, wherein the radiating section has a length. Theenergy applicator also includes a length adjustment member adapted toallow for selective adjustment of the length of the radiating section.

The present disclosure also relates to an electrosurgical systemincluding a generator and an ablation device. The ablation deviceincludes a feedline and a radiating section having a length, wherein theradiating section is operably coupled to the feedline. The ablationdevice also includes a radiation field adjustment member adapted toallow for selective adjustment of an ablation field radiated about theradiating section into tissue.

The present disclosure also relates to a method of directing energy totissue including the initial step of providing an energy applicator. Theenergy applicator includes a radiating section having a length. A distalportion of the radiating section includes an inner conductor and alength adjustment member electrically coupled to the inner conductor.The length adjustment member is adapted to allow for dimensionaladjustment of the radiating section. The method also includes the stepsof positioning the energy applicator in tissue, and transmitting energyfrom an energy source through the radiating section to generate anablation field radiating about at least a portion of the energyapplicator into tissue.

BRIEF DESCRIPTION OF THE DRAWINGS

Objects and features of the presently disclosed ablation devices withadjustable radiating section lengths, electrosurgical systems includingthe same, and methods of adjusting ablation fields using the same willbecome apparent to those of ordinary skill in the art when descriptionsof various embodiments thereof are read with reference to theaccompanying drawings, of which:

FIG. 1 is a schematic diagram of an ablation system including anablation device with adjustable radiating section lengths according toan embodiment of the present disclosure;

FIG. 2A is an enlarged view of the indicated area of detail of FIG. 1showing an embodiment of a length adjustment member in accordance withthe present disclosure;

FIG. 2B is a partial, perspective view of the ablation device of FIG. 1shown with the length adjustment member adjusted to elongate the distalradiating section according to an embodiment of the present disclosure;

FIG. 3 is a partial, cross-sectional view of an ablation device shownwith another embodiment of a length adjustment member in accordance withthe present disclosure;

FIG. 4 is an enlarged view of the indicated area of detail of FIG. 3according to an embodiment of the present disclosure;

FIG. 5 is a partial, cross-sectional view of the ablation device of FIG.3 shown with the length adjustment member adjusted to elongate thedistal radiating section according to an embodiment of the presentdisclosure;

FIG. 6 is a partial, cross-sectional view of the ablation device of FIG.3 shown with a gap adjustment member disposed proximal to the lengthadjustment member according to an embodiment of the present disclosure;

FIG. 7 shows a partial, cross-sectional view of the ablation device ofFIG. 6 shown with the length adjustment member adjusted to elongate thedistal radiating section and the gap adjustment member adjusted toshorten the distance across the gap at the feed point according to anembodiment of the present disclosure;

FIG. 8 shows a partial, cross-sectional view of the ablation device ofFIG. 6 shown with the length adjustment member adjusted to shorten thedistal radiating section and the gap adjustment member adjusted tolengthen the distance across the gap at the feed point according to anembodiment of the present disclosure;

FIG. 9 shows a diagram of a microwave ablation system that includes auser interface for displaying and controlling ablation patterns inaccordance with the present disclosure;

FIG. 10 is a block diagram of a microwave ablation system in accordancewith the present disclosure;

FIG. 11 is a partial, cross-sectional view of another embodiment of anablation device in accordance with the present disclosure;

FIG. 12 is a partial, perspective view of the ablation device of FIG. 11shown with a first operating element and a second operating element;

FIG. 13 is a schematic diagram of an ablation system including theablation device of FIG. 11 according to an embodiment of the presentdisclosure;

FIG. 14 is a flowchart illustrating a method of directing energy totissue according to an embodiment of the present disclosure; and

FIG. 15 is a flowchart illustrating a method of adjusting an ablationfield radiating into tissue.

DETAILED DESCRIPTION

Hereinafter, embodiments of the presently disclosed ablation deviceswith adjustable radiating section lengths, electrosurgical systemsincluding the same, and methods of adjusting ablation fields using thesame are described with reference to the accompanying drawings. Likereference numerals may refer to similar or identical elements throughoutthe description of the figures. As shown in the drawings and as used inthis description, and as is traditional when referring to relativepositioning on an object, the term “proximal” refers to that portion ofthe ablation device, or component thereof, closer to the user and theterm “distal” refers to that portion of the ablation device, orcomponent thereof, farther from the user.

This description may use the phrases “in an embodiment,” “inembodiments,” “in some embodiments,” or “in other embodiments,” whichmay each refer to one or more of the same or different embodiments inaccordance with the present disclosure. For the purposes of thisdescription, a phrase in the form “A/B” means A or B. For the purposesof the description, a phrase in the form “A and/or B” means “(A), (B),or (A and B)”. For the purposes of this description, a phrase in theform “at least one of A, B, or C” means “(A), (B), (C), (A and B), (Aand C), (B and C), or (A, B and C)”.

Electromagnetic energy is generally classified by increasing energy ordecreasing wavelength into radio waves, microwaves, infrared, visiblelight, ultraviolet, X-rays and gamma-rays. As it is used in thisdescription, “microwave” generally refers to electromagnetic waves inthe frequency range of 300 megahertz (MHz) (3×10⁸ cycles/second) to 300gigahertz (GHz) (3×10¹¹ cycles/second). As it is used in thisdescription, “ablation procedure” generally refers to any ablationprocedure, such as microwave ablation, radio frequency (RF) ablation ormicrowave ablation assisted resection. As it is used in thisdescription, “energy applicator” generally refers to any device that canbe used to transfer energy from a power generating source, such as amicrowave or RF electrosurgical generator, to tissue. As it is used inthis description, “energy applicator array” generally refers to one ormore energy applicators. As it is used in this description,“transmission line” generally refers to any transmission medium that canbe used for the propagation of signals from one point to another.

As it is used in this description, “length” may refer to electricallength or physical length. In general, electrical length is anexpression of the length of a transmission medium in terms of thewavelength of a signal propagating within the medium. Electrical lengthis normally expressed in terms of wavelength, radians or degrees. Forexample, electrical length may be expressed as a multiple orsub-multiple of the wavelength of an electromagnetic wave or electricalsignal propagating within a transmission medium. The wavelength may beexpressed in radians or in artificial units of angular measure, such asdegrees. The electric length of a transmission medium may be expressedas its physical length multiplied by the ratio of (a) the propagationtime of an electrical or electromagnetic signal through the medium to(b) the propagation time of an electromagnetic wave in free space over adistance equal to the physical length of the medium. The electricallength is in general different from the physical length. By the additionof an appropriate reactive element (capacitive or inductive), theelectrical length may be made significantly shorter or longer than thephysical length.

Various embodiments of the present disclosure provide ablation deviceswith adjustable radiating section lengths for treating tissue andmethods of directing electromagnetic radiation to tissue. Embodimentsmay be implemented using electromagnetic radiation at microwavefrequencies or at other frequencies. An electrosurgical system includingan ablation device with adjustable radiating section lengths, accordingto various embodiments, is designed and configured to operate betweenabout 300 MHz and about 10 GHz.

The ablation field radiated about an energy applicator into tissue isaffected by many factors including the antenna radiating section length,e.g., in relationship to microwave frequency. The ablation fieldradiated into tissue may also be affected by the gap distance of thefeed point, e.g., in the dipole antenna assembly. Ablation devicesaccording to embodiments of the present disclosure may include a lengthadjustment member (e.g., 350 shown in FIG. 3) adapted to allow fordimensional adjustment of a radiating section. In some embodiments, thepresently disclosed length adjustment members may be configured toeffect changes in the length of a distal radiating section. Embodimentsof ablation devices in accordance with the present disclosure mayadditionally, or alternatively, include a gap adjustment member (e.g.,640 shown in FIG. 6) adapted to allow for selective adjustment of thegap distance of the feed point.

Various embodiments of the presently disclosed ablation device withadjustable radiating section lengths are suitable for microwave ablationand for use to pre-coagulate tissue for microwave ablation assistedsurgical resection. Although various methods described hereinbelow aretargeted toward microwave ablation and the complete destruction oftarget tissue, it is to be understood that methods for directingelectromagnetic radiation may be used with other therapies in which thetarget tissue is partially destroyed or damaged, such as, for example,to prevent the conduction of electrical impulses within heart tissue. Inaddition, although the following description describes the use of adipole microwave antenna, the teachings of the present disclosure mayalso apply to a monopole, helical, or other suitable type of microwaveantenna.

FIG. 1 shows an electrosurgical system 10 according to an embodiment ofthe present disclosure that includes an energy applicator (also referredto herein as an ablation device) or probe 100. An embodiment of anenergy applicator suitable for use in tissue ablation applications, suchas the probe 100 of FIG. 1, in accordance with the present disclosure,is shown in more detail in FIGS. 2A and 2B. It will be understood,however, that other probe embodiments (e.g., 301, 601 and 901 shown inFIGS. 3, 6 and 11, respectively) may also be used.

Probe 100 generally includes an antenna assembly 12 having a radiatingportion 150 connected by a feedline 110 (or shaft) via a transmissionline 15 to a connector 16, which may further operably connect the probe100 to an electrosurgical power generating source, e.g., a microwave orRF electrosurgical generator, or a generator assembly 28. Probe 100according to various embodiments includes a radiating section 150 havinga length (e.g., “L” shown in FIGS. 1 and 2A). As shown in FIGS. 1 and2A, the probe 100 may include a length adjustment member 250 configuredto allow selective adjustment of the length of the radiating section150. An adjustment of the length of the radiating section 150 byadjusting the length adjustment member 250, which is described in moredetail later in this disclosure, may be made automatically or manuallyby the user.

Probe 100 may include a proximal radiating section 140 and a distalradiating section 105, which are described later in this disclosure. Insome embodiments, the radiating section 150 has a length “L” (shown inFIGS. 1 and 2A), and the distal radiating section 105 has a length “LD”(shown in FIG. 2A) and the proximal radiating section 140 has a length“L7” (shown in FIG. 2A), such that L=LD+L7. The shape and size of theantenna assembly 12 and the radiating section 150 may be varied from theconfiguration depicted in FIG. 1 (e.g., radiating section 150 may have alength “L1”, as shown in FIG. 2A).

Feedline 110 may be formed from a suitable flexible, semi-rigid or rigidmicrowave conductive cable, and may connect directly to anelectrosurgical power generating source 28. Alternatively, the feedline110 may electrically connect the antenna assembly 12 via thetransmission line 15 to the generator 28. Feedline 110 may have avariable length from a proximal end of the antenna assembly 12 to adistal end of transmission line 15 ranging from a length of about oneinch to about twelve inches. Feedline 110 may be formed of suitableelectrically-conductive materials, e.g., copper, gold, silver or otherconductive metals or metal alloys having similar conductivity values.Feedline 110 may be made of stainless steel, which generally offers thestrength required to puncture tissue and/or skin. Conductive materialsused to form the feedline 110 may be plated with other materials, e.g.,other conductive materials, such as gold or silver, to improve theirproperties, e.g., to improve conductivity, or decrease energy loss, etc.In some embodiments, the feedline 110 includes stainless steel, and toimprove the conductivity thereof, the stainless steel may be coated witha layer of a conductive material such as copper or gold. Feedline 110may include an inner conductor, a dielectric material coaxiallysurrounding the inner conductor, and an outer conductor coaxiallysurrounding the dielectric material. Antenna assembly 12 may be formedfrom a portion of the inner conductor (e.g., 210 shown in FIG. 2A) thatextends distal of the distal-most end of the outer conductor 260.Feedline 110 may be cooled by fluid, e.g., saline or water, to improvepower handling, and may include a stainless steel catheter.

In some embodiments, the power generating source 28 is configured toprovide microwave energy at an operational frequency from about 300 MHzto about 2500 MHz. In other embodiments, the power generating source 28is configured to provide microwave energy at an operational frequencyfrom about 300 MHz to about 10 GHz. Power generating source 28 may beconfigured to provide various frequencies of electromagnetic energy.Transmission line 15 may additionally, or alternatively, provide aconduit (not shown) configured to provide coolant fluid from a coolantsource 18 to the probe 100.

Antenna assembly 12 generally includes an inner conductor 210, an outerconductor 260, and may include a dielectric material 240 separating theinner conductor 210 and the outer conductor 260. Length adjustmentmember 250 according to various embodiments is electrically coupled tothe inner conductor 210 by any suitable manner of electrical connection,e.g., soldering, welding, or laser welding. In some embodiments, theinner conductor 210 is formed from a first electrically-conductivematerial (e.g., stainless steel) and the outer conductor 260 is formedfrom a second electrically-conductive material (e.g., copper). In someembodiments, the outer conductor 260 coaxially surrounds the innerconductor 210 along at least a portion of the antenna assembly 12. Innerconductor 210 and the outer conductor 260 may be formed from anysuitable electrically-conductive material.

According to embodiments of the present disclosure, the distal end ofthe outer conductor 260 may be spaced apart by a gap (e.g., “G” shown inFIGS. 6 and 8) from the proximal end of the distal radiating section todefine a feed point (e.g., 635 shown in FIG. 6) therebetween. Electricalchokes or non-electrical (fluid) chokes may be used to contain returningcurrents to the distal end of the antenna assembly 12, e.g., to improvethe energy focus of an antenna assembly 12. Generally, the choke may bedisposed on the antenna assembly 12 proximally of or as a part of theradiating section.

The dielectric material 240 may be formed from any suitable dielectricmaterial, including, but not limited to, ceramics, water, mica,polyethylene, polyethylene terephthalate, polyimide,polytetrafluoroethylene (PTFE) (e.g., TEFLON®, manufactured by E.I. duPont de Nemours and Company of Wilmington, Del., United States), glass,or metal oxides. Antenna assembly 12 may be provided with a seconddielectric material (e.g., 270 shown in FIG. 2A) surrounding the outerconductor 260, or portions thereof. In some embodiments, the seconddielectric material is formed from a material with a dielectric constantdifferent than the dielectric constant of the dielectric material 240.

Located at the distal end of the antenna assembly 12 is an end cap ortapered portion 120, which may terminate in a sharp tip 123 to allow forinsertion into tissue with minimal resistance. The end cap or taperedportion 120 may include other shapes, such as, for example, a tip 123that is rounded, flat, square, hexagonal, or cylindroconical. Tip 123may be coated with a non-stick material, such as polytetrafluoroethylene(a.k.a. PTFE or TEFLON®, manufactured by the E.I. du Pont de Nemours andCompany of Wilmington, Del., United States), polyethylene tephthalate(PET), or the like.

In some variations, the antenna assembly 12 includes a proximalradiating section 140 and a distal radiating section 105. In someembodiments, a junction member (not shown), which is generally made of adielectric material couples the proximal radiating section 140 and thedistal radiating section 105. In some embodiments, the distal andproximal radiating sections 105, 140 align at the junction member andare also supported by the inner conductor that extends at leastpartially through the distal radiating section 105. The junction memberaccording to various embodiments may be formed from any suitableelastomeric or ceramic dielectric material by any suitable process. Insome embodiments, the junction member is formed by overmolding andincludes a thermoplastic elastomer, such as, for example, polyetherblock amide (e.g., PEBAX®, manufactured by The Arkema Group of Colombes,France), polyetherimide (e.g., ULTEM® and/or EXTEM®, manufactured bySABIC Innovative Plastics of Saudi Arabia) and/or polyimide-basedpolymer (e.g., VESPEL®, manufactured by E. I. du Pont de Nemours andCompany of Wilmington, Del., United States). The junction member may beformed using any suitable overmolding compound by any suitable process,and may include use of a ceramic substrate. Examples of junction memberembodiments are disclosed in commonly assigned U.S. patent applicationSer. No. 12/701,030 filed on Feb. 5, 2010, entitled “ELECTROSURGICALDEVICES WITH CHOKE SHORTED TO BIOLOGICAL TISSUE”.

In some embodiments, the antenna assembly 12 may be provided with acoolant chamber (not shown). Additionally, the junction member mayinclude coolant inflow and outflow ports (not shown) to facilitate theflow of coolant into, and out of, the coolant chamber. Examples ofcoolant chamber and coolant inflow and outflow port embodiments aredisclosed in commonly assigned U.S. patent application Ser. No.12/401,268 filed on Mar. 10, 2009, entitled “COOLED DIELECTRICALLYBUFFERED MICROWAVE DIPOLE ANTENNA”, and U.S. Pat. No. 7,311,703,entitled “DEVICES AND METHODS FOR COOLING MICROWAVE ANTENNAS”.

In some embodiments, the antenna assembly 12 may be provided with anouter jacket (not shown) disposed about the distal radiating section105, or portions thereof, the proximal radiating section 140, orportions thereof, and/or the feedline 110, or portions thereof. Theouter jacket may be formed of any suitable material, such as, forexample, polymeric or ceramic materials. The outer jacket may be appliedby any suitable method, such as, for example, heat shrinking,overmolding, coating, spraying dipping, powder coating, baking and/orfilm deposition.

During microwave ablation, e.g., using the electrosurgical system 10,the probe 100 is inserted into or placed adjacent to tissue andmicrowave energy is supplied thereto. Ultrasound or computed tomography(CT) guidance may be used to accurately guide the probe 100 into thearea of tissue to be treated. Probe 100 may be placed percutaneously oratop tissue, e.g., using conventional surgical techniques by surgicalstaff. A clinician may pre-determine the length of time that microwaveenergy is to be applied. Application duration may depend on many factorssuch as tumor size and location and whether the tumor was a secondary orprimary cancer. The duration of microwave energy application using theprobe 100 may depend on the progress of the heat distribution within thetissue area that is to be destroyed and/or the surrounding tissue.Single or multiple probes 100 may be used to provide ablations in shortprocedure times, e.g., a few seconds to minutes, to destroy cancerouscells in the target tissue region.

A plurality of probes 100 may be placed in variously arrangedconfigurations to substantially simultaneously ablate a target tissueregion, making faster procedures possible. Multiple probes 100 can beused to synergistically create a large ablation volume or to ablateseparate sites simultaneously. Tissue ablation size and geometry isinfluenced by a variety of factors, such as the energy applicatordesign, number of energy applicators used simultaneously, ablation timeand wattage, and tissue characteristics.

In operation, microwave energy having a wavelength, lambda (λ), istransmitted through the antenna assembly 12, e.g., along the distalradiating section 105, and radiated into the surrounding medium, e.g.,tissue. The length of the antenna for efficient radiation may bedependent on the effective wavelength, λ_(eff), which is dependent uponthe dielectric properties of the medium being radiated into. Antennaassembly 12 through which microwave energy is transmitted at awavelength, λ, may have differing effective wavelengths, λ_(eff),depending upon the surrounding medium, e.g., liver tissue as opposed tobreast tissue.

As shown in FIGS. 1 and 2A, the antenna assembly 12 according toembodiments of the present disclosure includes a length adjustmentmember 250 adapted to allow for dimensional adjustment of the radiatingsection 150. Length adjustment member 250 according to variousembodiments includes a sleeve portion 255 including a proximal end 254and a distal end 256. Sleeve portion 255 may have a substantiallycylindrical or tubular shape and may be formed from stainless steel.Tapered portion 120 may be disposed adjacent to the distal end 256 ofthe sleeve portion 255. Tapered portion 120 may be formed of a firstelectrically-conductive material and the sleeve portion 255 may beformed of a second electrically-conductive material different than thefirst electrically-conductive material. Tapered portion 120 may beformed of a material with high thermal conductivity. The shape and sizeof the sleeve portion 255 and the tapered portion 120 may be varied fromthe configuration depicted in FIGS. 1 and 2A.

In some embodiments, the antenna assembly 12 includes an insulatorsleeve 270 disposed around at least a portion of the outer conductor260. As shown in FIG. 2A, the sleeve portion 255 may be disposed aroundat least a distal portion 272 of the insulator sleeve 270. In someembodiments, the insulator sleeve 270 and the sleeve portion 255 may besubstantially concentric to a longitudinal axis (e.g., “A-A” shown inFIG. 2A) of the inner conductor 210. Insulator sleeve 270 may extenddistally beyond the distal end 256 of the outer conductor 260, e.g., toenhance slideability and/or repositionability of the sleeve portion 255.The shape and size of the insulator sleeve 270 may be varied from theconfiguration depicted in FIGS. 2A and 2B.

Insulator sleeve 270 may be formed of any suitable non-conductiveinsulator, e.g., a TEFLON® sleeve. In some embodiments, the insulatorsleeve 270 is a lubricous sleeve. Insulator sleeve 270 may be applied byany suitable manner, including, but not limited to, by applying apolymeric coating, and/or by positioning a heat-shrinkable tube (e.g.,polyolefin) and raising the temperature thereof to conform the heatshrink tubing to the outer conductor 260. Insulator sleeve 270 may beselected based on materials properties, e.g., density and lubricity, toallow for sliding of the sleeve portion 255, or portions thereof, overthe insulator sleeve 270. Insulator sleeve 270 may additionally, oralternatively, be selected to prevent damage and/or minimize wear to theinsulator sleeve 270 and/or the sleeve portion 255. Insulator sleeve 270may be formed of a lubricous polymeric material, such as a high-densitypolyolefin (e.g., polyethylene), polytetrafluoroethylene (a.k.a. PTFE orTEFLON®, manufactured by E. I. du Pont de Nemours and Company ofWilmington, Del., United States), or polyurethane. Insulator sleeve 270may be formed by heat-shrinkage, extrusion, molding, dip coating, orother suitable process. In some embodiments, the insulator sleeve 270may include a surface coating formed of highly hydrophilic, low-frictionpolymer, such as polyvinylpyrrolidone, polyethyleneoxide,polyhydroxyethylmethacrylate, or copolymers thereof. Insulator sleeve270 may be formed from a material with a dielectric constant that ishigher than the dielectric constant of the dielectric material 240,e.g., to maximize energy radiated into the surrounding medium, e.g.,tissue. Insulator sleeve 270 may be formed of materials that can be madehydrophilic for a predetermined period of time during the procedure,e.g., by contact with water and/or other bodily fluids such as blood.

Length adjustment member 250 according to various embodiments may have afirst position (e.g., a proximal-most position) corresponding to aradiating section 150 having a relatively short length “L1” (shown inFIG. 2A), a second position (e.g., a distal-most position),corresponding to a radiating section 150L having a relatively longlength “L3” (shown in FIG. 2B), and a plurality of intermediatepositions corresponding to radiating sections of intermediate lengths.In some embodiments, the distance “L1” is about 1 cm, and the distance“L3” may be about 5 cm.

In some embodiments, when the length adjustment member 250 is positionedin a first position, e.g., corresponding to a radiating section 150having a relatively short length “L1” (shown in FIG. 2A), the distalportion 250 of the antenna radiating section extends by a fixed length“LD” distally beyond the proximal radiating section 22, which is formedby the exposed portion of the underlapping outer conductor, and has alength “L2”, such that L1=LD+L2. As shown in FIG. 2B, when the lengthadjustment member 250 is placed in a second position, e.g.,corresponding to a radiating section 150L having a relatively longlength “L3”, the distal portion 250 of radiating section still extendsby the fixed length “LD” distally beyond the proximal radiating section22, which has a length “L4”, such that L3=LD+L4. The distances “L2” and“L4” may be any suitable length and may be measured in fractions of awavelength. In some embodiments, the distance “L2” is about 1 mm, andthe distance “L4” may be about 4 cm.

Selective adjustment of the length adjustment member 250, according tovarious embodiments, allows a portion of the underlapping outerconductor extending proximally to the length adjustment member 250 to bevaried in length, which may enhance microwave performance of the probe100 and/or provide a desired ablation volume and shape. For example, aradiating section (e.g., 150 shown in FIG. 2A) having a relatively shortlength, e.g., “L1”, for use to generate local temperatures that resultin a small ablation volume may be suitable for treatment of a smalltumor, e.g., using a frequency of 915 MHz. In a resection procedure,where the surgeon may want to extend the distal radiating section as fardistally as possible, a radiating section (e.g., 150L shown in FIG. 2B)having a relatively long length, e.g., “L3”, may be fashioned by usingthe length adjustment member 250 to adjust the length of the proximalradiating section. During a procedure, selective adjustment of thelength of the proximal radiating section using the length adjustmentmember 250 may be carried out any number of times, e.g., to enhancemicrowave performance of the probe 100 and/or provide a desired ablationpattern.

Probe 100 may be configured to operate with a directional radiationpattern. Probe 100 may be rotatable about a longitudinal axis “A-A”(shown in FIG. 2A) such that the directional radiation pattern rotatestherewith. Examples of antenna assemblies rotatable about axis “A-A”such that any elongated radiation lobes rotates therewith are disclosedin commonly assigned U.S. patent application Ser. No. 12/197,405 filedon Aug. 25, 2008, entitled “MICROWAVE ANTENNA ASSEMBLY HAVING ADIELECTRIC BODY PORTION WITH RADIAL PARTITIONS OF DIELECTRIC MATERIAL”.

FIG. 3 shows a portion of an ablation device 301 according to anembodiment of the present disclosure that includes an inner conductor210, a dielectric material 240 disposed coaxially around the innerconductor 210, and a length adjustment member 350 adapted to allow fordimensional adjustment of a distal radiating section 305. As shown inFIG. 3, the inner conductor 210 may extend distally beyond thedielectric material 240. Inner conductor 210 may be formed from ayieldable or flexible material.

As cooperatively shown in FIGS. 3 and 5, the length adjustment member350 may have a first position (e.g., a proximal-most position)corresponding to a distal radiating section 305 having a relativelyshort length “L5”, a second position (e.g., a distal-most position),corresponding to a distal radiating section 305L having a relativelylong length “L6”, and a plurality of intermediate positionscorresponding to distal radiating sections of intermediate lengths. Insome embodiments, the distance “L5” is about 1 cm, and the distance “L6”may be about 5 cm. In some embodiments, the length adjustment member 350includes a tapered end portion (e.g., 355 shown in FIG. 3) thatterminates in a sharp tip (e.g., 338 shown in FIG. 3) at the distal endof the distal radiating section. The tapered end portion allows forinsertion of the probe into tissue with minimal resistance. The taperedend portion may include other shapes, such as, for example, a tip thatis rounded, flat, square, hexagonal, or cylindroconical.

Length adjustment member 350 according to various embodiments includesan inner sleeve 352 and an outer sleeve 351 disposed around at least aportion of the inner sleeve 352. Outer sleeve 351 and the inner sleeve352 may be of different sizes, diameters and thickness. As shown inFIGS. 3 and 4, the inner sleeve 352 may include a proximal end portion353, a distal end portion 354 and a threaded middle portion 357 disposedbetween the proximal and distal end portions 353, 354, and the outersleeve 351 may include a tapered end portion 355, a middle portion 356,and a threaded end portion 358 engaged with the threaded middle portion357 of the inner sleeve 352. Outer sleeve 351 and the inner sleeve 352may be formed of any suitable electrically-conductive material, e.g.,metal such as stainless steel, titanium, etc. In some embodiments, theinner sleeve 352 may be formed of any rigid dielectric material. Theshape and size of the outer sleeve 351 and the inner sleeve 352 may bevaried from the configuration depicted in FIGS. 3 through 5.

When the length adjustment member 350 is positioned in a first position(e.g., a proximal-most position), a second position (e.g., a distal-mostposition) or an intermediate position between the first and secondpositions, a plurality of threads (e.g., 358 a shown in FIG. 4) of thethreaded end portion 358 engage with a plurality of threads (e.g., 357 ashown in FIG. 4) of the threaded middle portion 357. As shown in FIGS. 3and 4, when the outer sleeve 351 is placed in a proximal-most position,the threaded end portion 358 engages with a proximal portion of thethreaded middle portion 357 disposed closest to the proximal end portion353 of the inner sleeve 352. As shown in FIG. 5, when the outer sleeve351 is placed in a distal-most position, the threaded end portion 358engages with a distal portion of the threaded middle portion 357disposed closest to the distal end portion 354 of the inner sleeve 352.

In some embodiments, the distal end portion 354 of the inner sleeve 352may include a mechanical interface configured to engage the middleportion 356 of the outer sleeve 351. As shown in FIG. 3, the distal endportion 354 of the inner sleeve 352 may include a protrusion 354 pconfigured to slideably engage an inner surface of the middle portion356 of the outer sleeve 351, e.g., to enhance structural integrity ofthe length adjustment member 350 and/or maintain proper alignment of thethreads 357 a, 358 a. The shape and size of the protrusion 354 p may bevaried from the configuration depicted in FIGS. 3 and 5. In someembodiments, friction on the outer sleeve 351 may be reduced byminimizing the surface area of the protrusion 354 p that contacts theinner surface of the middle portion 356 of the outer sleeve 351.

Ablation device 301, or portions thereof, may be provided with aflexible, outer coating or jacket material 322. In some embodiments, thejacket material 322 may be disposed around the length adjustment member350, or portions thereof. Any material having suitable materialproperties, e.g., elasticity, may be used for the jacket material 322,e.g., a stretchable polymer heat shrink.

In some embodiments, the length adjustment member 350 can be made longeror shorter in length by spinning the inner sleeve 352 and the outersleeve 351 in relationship to one another. The elastic, resilience oryieldable properties of the inner conductor 210 may allow a coiledportion of the inner conductor 210 to wind or unwind, e.g., as thelength adjustment member 350 is adjusted.

Ablation device 301 according various embodiments may be adapted toallow for selective adjustment of the length of the distal radiatingsection using the length adjustment member 350 during an automaticadjustment process, e.g., to adjust the ablation field radiated intotissue. Ablation device 301 may be rotatable about a longitudinal axissuch that a directional radiation pattern rotates therewith.

FIG. 6 shows a portion of an ablation device 601 according to anembodiment of the present disclosure that is similar to the portion ofthe ablation device 301 of FIG. 3, except for a gap adjustment member640, which is described later in this disclosure, disposed proximal tothe length adjustment member 350. Ablation device 601 includes an innerconductor 210, a dielectric material 240 disposed coaxially around theinner conductor 210, and an outer conductor 260, and may include aninsulator sleeve 270 disposed around the dielectric material 240, orportions thereof. The inner conductor 210, the dielectric material 240,and the insulator sleeve 270 shown in FIG. 6 are similar to the elementsdesignated with like reference numerals in FIGS. 3 through 5, andfurther description thereof is omitted in the interests of brevity.

Embodiments of the ablation device 601 may include the length adjustmentmember 350 shown in FIGS. 3 through 5. Length adjustment member 350 maybe adjustable to a distal-most position, a proximal-most position, and aplurality of intermediate positions. As shown in FIG. 7, when the outersleeve 351 is placed in a distal-most position, the threaded end portion358 engages with a distal portion of the threaded middle portion 357disposed closest to the distal end portion 354 of the inner sleeve 352,corresponding to a distal radiating section 305L having a relativelylong length (e.g., “L6” shown in FIG. 5). As shown in FIG. 8, when theouter sleeve 351 is placed in a proximal-most position, the threaded endportion 358 engages with a proximal portion of the threaded middleportion 357 disposed closest to the proximal end portion 353 of theinner sleeve 352, corresponding to a distal radiating section 305 havinga relatively short length (e.g., “L5” shown in FIG. 3). The shape andsize of the length adjustment member 350 may be varied from theconfigurations depicted in FIG. 6 and FIGS. 7 and 8.

Outer conductor 660 may be formed from any suitableelectrically-conductive material, e.g., metal such as copper, aluminum,stainless steel, or other suitable metal. As shown in FIG. 6, the distalend 662 of the outer conductor 660 may be spaced apart by a gap “G” fromthe proximal end of the distal radiating section 305 to define a feedpoint 635 therebetween.

Gap adjustment member 640 according to various embodiments is adapted toallow for selective adjustment of the gap distance of the feed point635, e.g., to enhance microwave performance of the probe 100 and/orprovide a desired ablation pattern. For example, when a smaller ablationwith a more spherical or donut shape ablation is desired, the ablationdevice 601 may be adjusted to its most compact length with a reducedradiating section tuning point, e.g., one-quarter wavelength in tissue.When an ablation device is needed to produce longer, narrower ablations(e.g., in resection procedures) the gap and the distal radiating sectionlength may be expanded to fuller lengths by adjusting the gap adjustmentmember 640 and the length adjustment member 350. In some embodiments,the gap adjustment member 640 and/or the length adjustment member 350may be adjusted manually by the user and/or automatically, e.g., by thepresently disclosed electrosurgical system 1000 (shown in FIG. 9). Gapadjustment member 640 according to embodiments may take a variety offorms, e.g., moveable sleeves and/or moveable arms, with or withoutlubrication.

Gap adjustment member 640 may be formed of any suitableelectrically-conductive material, e.g., metal such as copper, stainlesssteel, titanium, etc. As shown in FIG. 6, the gap adjustment member 640may be coaxially disposed around an insulator sleeve 270 disposed aroundthe dielectric material 240. Gap adjustment member 640 may be configuredto move, e.g., slide, longitudinally along the insulator sleeve 270 in adistal-to-proximal direction, e.g., to shorten the gap distance of thefeed point 635, and a proximal-to-distal direction, e.g., to lengthenthe gap distance of the feed point 635 (as shown by the double-arrowheadlines in FIG. 6). In some embodiments, the gap adjustment member 640 maybe coaxially disposed around the dielectric material 240, wherein thedielectric material 240 has material properties, e.g., density, to allowfor sliding of the gap adjustment member 640 along the outer surface ofthe first dielectric material without damage to the dielectric material240 and/or the gap adjustment member 640. Outer conductor 660 iselectrically coupled to the gap adjustment member 640. In someembodiments, the distal end portion 66 of the outer conductor 260 iscoaxially disposed around at least a portion of the gap adjustmentmember 640. The outer surface of the gap adjustment member 640, orportions thereof, may be coated with a suitable lubricious substance(not shown) to aid in the movement of the gap adjustment member 640. Thelubricious substance may be an electrically-conductive substance. Theshape and size of the gap adjustment member 640 may be varied from theconfiguration depicted in FIG. 6.

An outer jacket (not shown) may be provided to the probe 601, orportions thereof, e.g., disposed proximal to the distal radiatingsection. In some embodiments, the outer jacket may be made of aninsulating material, such as, for example, a polyimide or similardielectric material. The outer jacket may be a water-cooled catheterformed of a material having low electrical conductivity. During use,coolant may circulate through the outer jacket, which may help controlthe temperature of the probe 601, and may provide dielectric loadingwithin the radiating section. The outer surface of the outer jacket maybe coated with a suitable lubricious substance, such as TEFLON®, to aidin the movement of the outer jacket in or through tissue as well as toaid in preventing tissue from sticking thereto.

Ablation device 601 may include an indicia alignment mark (not shown)such as a colored strip or the like (e.g., to provide a visual cue tothe surgeon to allow orientation of the direction of flow of the energyto coincide with the indicia alignment mark) and/or indicia graduationmarks (not shown) for insertion depth reference. Examples of indiciaalignment mark and the indicia graduation mark embodiments are disclosedin commonly assigned U.S. patent application Ser. No. 12/476,960 filedon Jun. 2, 2009, entitled “ELECTROSURGICAL DEVICES WITH DIRECTIONALRADIATION PATTERN”.

Ablation device 601 according to various embodiments is adapted to allowthe surgeon to adjust the length of the distal radiating section and thegap distance of the feed point to any suitable configuration, e.g., toadjust the ablation field and/or achieve a desired surgical outcome. Forexample, as shown in FIG. 7, the length adjustment member 350 may beadjusted to provide an elongated distal radiating section 305L, and thegap adjustment member 640 according to an embodiment of the presentdisclosure may be distally extended from the distal end 662 of the outerconductor 660 by a length “L8” to shorten the gap distance of the feedpoint to a length “L9”, which may correspond to a relatively small gapdistance. In some embodiments, the distance “L8” is about 5 mm, and thedistance “L9” may be about 0.5 mm. As shown in FIG. 8, the lengthadjustment member 350 may be adjusted to provide a distal radiatingsection 305 having a relatively short length, and the gap adjustmentmember 640 according to an embodiment of the present disclosure may beadjusted by a length “L10” to provide a gap distance of a length “L11”,e.g., to adjust the ablation field. In some embodiments, the distance“L10” is about 0.5 mm, and the distance “L11” may be about 10 mm.

FIG. 9 schematically illustrates an electrosurgical system 1000according to an embodiment of the present disclosure including theablation device or probe 601. It will be understood, however, that otherprobe embodiments (e.g., 301 and 901 shown in FIGS. 3 and 9,respectively) may also be used. Electrosurgical system 1000 includes anactuator 20 operably coupled to an embodiment of the generator assembly28 of the electrosurgical system 10 of FIG. 1. Actuator 20 may be afootswitch operably coupled by a cable 19 via connector 17 to thegenerator assembly 28, a handswitch, a bite-activated switch, or anyother suitable actuator. Cable 19 may include one or more electricalconductors for conveying an actuation signal from the actuator 20 to thegenerator assembly 28. In an embodiment, the actuator 20 is operablycoupled to the generator assembly 28 by a wireless link, such as withoutlimitation, a radiofrequency or infrared link. In use, the clinician mayinteract with the user interface 25 to preview operationalcharacteristics of the ablation device 601.

Generator assembly 28, according to various embodiments, includes agenerator module (e.g., 86 shown in FIG. 10) in operable communicationwith a processor (e.g., 82 shown in FIG. 10), a user interface 25, andan actuator 20. Ablation device 601 is operably coupled to an energyoutput of the generator module, which may be configured as a source ofRF and/or microwave energy. Actuator 20 is operably coupled to theprocessor via the user interface 25. In embodiments, actuator 20 may beoperably coupled to the processor and/or to the generator module by acable connection or a wireless connection.

User interface 25 may include a display 21, such as without limitation aflat panel graphic LCD (liquid crystal display), adapted to visuallydisplay at least one user interface element 23, 24. In an embodiment,display 21 includes touchscreen capability (not shown), e.g., theability to receive input from an object in physical contact with thedisplay, such as without limitation, a stylus or a user's fingertip. Auser interface element 23, 24 may have a corresponding active region,such that, by touching the screen within the active region associatedwith the user interface element, an input associated with the userinterface element 23, 24 is received by the user interface 25.

User interface 25 may additionally, or alternatively, include one ormore controls 22 that may include without limitation a switch (e.g.,pushbutton switch, toggle switch, slide switch) and/or a continuousactuator (e.g., rotary or linear potentiometer, rotary or linearencoder). In an embodiment, a control 22 has a dedicated function, e.g.,display contrast, power on/off, and the like. Control 22 may also have afunction that may vary in accordance with an operational mode of theelectrosurgical system 1000. A user interface element 23 may bepositioned substantially adjacently to control 22 to indicate thefunction thereof. Control 22 may also include an indicator, such as anilluminated indicator, e.g., a single- or variably-colored LEDindicator.

FIG. 10 is a block diagram showing one embodiment of the electrosurgicalsystem 1000 of FIG. 9. In an embodiment, the generator module 86 isconfigured to provide energy of about 915 MHz. Generator module 86 mayadditionally, or alternatively, be configured to provide energy of about2450 MHz (2.45 GHz). The present disclosure contemplates embodimentswherein the generator module 286 is configured to generate a frequencyother than about 915 MHz or about 2450 MHz, and embodiments wherein thegenerator module 86 is configured to generate variable frequency energy.Generator assembly 28 includes a processor 82 that is operably coupledto the user interface 25. Processor 82 may include any type of computingdevice, computational circuit, or any type of processor or processingcircuit capable of executing a series of instructions that are stored ina memory, e.g., storage device 88 or external device 91.

In some embodiments, a storage device 88 is operably coupled to theprocessor 82, and may include random-access memory (RAM), read-onlymemory (ROM), and/or non-volatile memory (NV-RAM, Flash, and disc-basedstorage.) Storage device 88 may include a set of program instructionsexecutable on the processor 82 for executing a method for displaying andcontrolling ablation patterns in accordance with the present disclosure.Generator assembly 200 may include a data interface 90 that isconfigured to provide a communications link to an external device 91. Insome embodiments, the data interface 90 may be any of a USB interface, amemory card slot (e.g., SD slot), and/or a network interface (e.g., 100BaseT Ethernet interface or an 802.11 “Wi-Fi” interface.) Externaldevice 91 may be any of a USB device (e.g., a memory stick), a memorycard (e.g., an SD card), and/or a network-connected device (e.g.,computer or server).

Generator assembly 28 may also include a database 84 that is configuredto store and retrieve energy applicator data, e.g., parametersassociated with one or energy applicators (e.g., 901 shown in FIG. 11).Parameters stored in the database 84 in connection with an energyapplicator, or energy applicator array assembly, may include, but arenot limited to, energy applicator (or applicator array assembly)identifier, energy applicator (or applicator array assembly) dimensions,a frequency, an ablation length (e.g., in relation to a radiatingsection length), an ablation diameter, a gap distance at the feed point(e.g. in relation to an ablation geometry), a temporal coefficient, ashape metric, and/or a frequency metric. In an embodiment, ablationpattern topology may be included in the database 84, e.g., a wireframemodel of an applicator array assembly and/or an ablation patternassociated therewith.

Database 84 may also be maintained at least in part by data provided bythe external device 91 via the data interface 90. For example withoutlimitation, energy applicator data may be uploaded from an externaldevice 91 to the database 84 via the data interface 90. Energyapplicator data may additionally, or alternatively, be manipulated,e.g., added, modified, or deleted, in accordance with data and/orinstructions stored on the external device 91. In an embodiment, the setof energy applicator data represented in the database 84 isautomatically synchronized with corresponding data contained in theexternal device 91 in response to the external device 91 being coupled(e.g., physical coupling and/or logical coupling) to the data interface90.

Processor 82 according to various embodiments is programmed to enable auser, via the user interface 25 and/or the display 21, to view at leastone ablation pattern and/or other energy applicator data correspondingto an embodiment of an applicator array assembly. For example, a surgeonmay determine that a substantially spherical ablation pattern isnecessary. The surgeon may activate a “select ablation shape” mode ofoperation for generator assembly 28, preview an energy applicator arrayby reviewing graphically and textually presented data on the display 21,optionally, or alternatively, manipulate a graphic image by, forexample, rotating the image, and select an array of energy applicatorsbased upon displayed parameters. The selected energy applicator(s) maythen be electrically coupled to the generator assembly 28 for usetherewith.

In an embodiment, a surgeon may input via the user interface 25 anapplicator array parameter to cause the generator assembly 28 to presentone or more electromagnetic energy delivery devices correspondingthereto. For example, a surgeon may require a 3.0 cm×3.0 cm×3.0 cmablation pattern, and provide an input corresponding thereto. Inresponse, the generator assembly 28 may preview a corresponding subsetof available electromagnetic energy delivery devices that match orcorrelate to the inputted parameter.

In an embodiment, a surgeon may input via the user interface 25 aselected power output, and the electrosurgical system 1000 controls theablation device 601 to automatically thread out, or thread in, the outersleeve 358 of the length adjustment member 350 to adjust the length ofthe distal radiating section 305, e.g., to adjust the ablation fieldradiated into tissue. Electrosurgical system 1000 may automaticallythread out, or thread in, the outer sleeve 358 to adjust the length ofthe distal radiating section 305 based on the power level and/or levelof reflected power.

Electrosurgical system 1000 may additionally, or alternatively, beadapted to control the ablation device 601 to automatically adjust thegap adjustment member 640 to shorten, or lengthen, the gap distance ofthe feed point 635. Electrosurgical system 1000 according to variousembodiments may include a feedback looping mechanism suitable for use incontrolling an embodiment of an ablation device (e.g., 601 shown in FIG.6 or 901 shown in FIG. 11). The feedback looping mechanism may include,without limitation, proximity sensors, a voltage divider network, radialsensors, and/or feedback clicks, e.g., based upon the thread ratio ofthe threads 357 a, 358 a.

In another embodiment, the electrosurgical system 1000 may be adapted tocontrol the ablation device 901 (shown in FIG. 11), and may include afirst actuator (e.g., operably coupled to a first pivot element of theablation device 901) and/or a second actuator (e.g., operably coupled toa second pivot element of the ablation device 901) to allow forautomatic adjustment of the ablation field radiated into tissue. Asdescribed in more detail later in this disclosure, a first actuator maybe used to automatically adjust an ablation field by adjusting thelength of a distal radiating section using a length adjustment member(e.g., 950 shown in FIG. 11), and/or a second actuator may be used toadjust an ablation field by adjusting the gap distance of a feed pointusing a gap adjustment member (e.g., 940 shown in FIG. 11).

FIG. 11 shows a portion of an ablation device 901 according to anotherembodiment of the present disclosure including a distal radiatingsection 905, a length adjustment member 950 adapted to allow fordimensional adjustment of the distal radiating section 905. Ablationdevice 901 may additionally, or alternatively, include a gap adjustmentmember 940 adapted to allow for selective adjustment of the gap distanceof a feed point 935. As shown in FIG. 11, the ablation device 901generally includes an inner conductor 210 having a proximal end 912, adielectric material 240 disposed coaxially around the inner conductor210, an outer conductor 960 disposed coaxially around at least aproximal portion of the dielectric material 240. In some embodiments,the inner conductor 210 is formed from a first electrically-conductivematerial (e.g., stainless steel) and the outer conductor 260 is formedfrom a second electrically-conductive material (e.g., copper). Innerconductor 210 may be electrically coupled to the length adjustmentmember 950.

Length adjustment member 950 according to various embodiments includesan inner sleeve 952 having an inner surface 91 disposed about a proximalportion 943 of dielectric material (e.g., dielectric material 240 orother dielectric including without limitation, plastic ceramic or air),and an outer sleeve 951 disposed around at least a portion of an outersurface 92 of the inner sleeve 952. Outer sleeve 951 and the innersleeve 952 may be formed of any suitable electrically-conductivematerial, e.g., metal such as stainless steel, titanium, etc. Outersleeve 951 and the inner sleeve 952 may be of different sizes, diametersand thickness. The shape and size of the outer sleeve 951 and the innersleeve 952 may be varied from the configuration depicted in FIG. 11.

In some embodiments, the inner sleeve 952 includes a hollow body 954,e.g., having a substantially cylindrical or tubular shape, and an endcap 953 adapted to close an open end of the hollow body. End cap 953includes an inner surface 95 and an outer surface 97, and may have agenerally circular or disc-like shape. As shown in FIG. 11, the end cap953 may be provided with an aperture configured to allow passage of theproximal end 912 of the inner conductor 210 therethrough. In someembodiments the inner conductor 210 is electrically coupled to the endcap 953.

As shown in FIG. 11, the outer sleeve 951 may include a tubular body 956defining a chamber “C”, e.g., configured to receive at least a portionof the inner sleeve 952, and a tapered end portion 955 extendingdistally of a distal end of the sleeve body 956. In some embodiments,the tapered end portion 955 includes an inner surface 95 and an innercavity 95 a defined by the inner surface 95. As shown in FIG. 11, theinner cavity 95 a may include an open end in communication with thechamber “C”. The shape and size of chamber “C” and the cavity 95 a maybe varied from the configuration depicted in FIG. 11.

Length adjustment member 950 according to various embodiments includes afirst biasing member 983. First biasing member 983 may be any suitablebiasing member, e.g., a spring. First biasing member 983 may beconfigured to fit within the chamber “C” and/or the cavity 95 a. In someembodiments, the first biasing member 983 is adapted to exert a biasingforce against a proximal wall of the cavity 95 a. In some embodiments,the distal end 242 of the dielectric material 240 may be disposedadjacent to the inner surface 94 of the end cap 953 to help prevent orminimize movement of the inner sleeve 952, proximally, e.g., when aforce is exerted on the outer surface 97 of the end cap 953. As shown inFIG. 11, the first biasing member 983 may include an interior open space(e.g., defined by coils of a spring) configured to allow the conductor210 to extend distally from the outer surface 97 of the end cap 953 intothe chamber “C” and/or the cavity 95 a. First biasing member 983according to various embodiments is adapted to exert a biasing forcesufficient to cause the outer sleeve 951 to move, distally, a length“L12”. In some embodiments, the distance “L12” is in the range of about3 cm to about 10 cm.

In some embodiments, where the first biasing member 983 is a coilspring, the biasing force may be a function of material propertiesand/or specific configuration of the spring, e.g., diameter of thespring wire, coil length and number of turns per unit length. In anembodiment, the first biasing member 983 is formed of a material havinga known coefficient of thermal expansion, e.g., to allow for adjustingof the biasing force through the application of heat to the firstbiasing member 983.

As shown in FIG. 11, the outer sleeve 951 may be operably associatedwith a first tensioning element 994, e.g., a cable, coupled to a firstpivot element 997, e.g., a pin and spool mechanism. In some embodiments,the length adjustment member 950 can be made longer or shorter byrotating the first pivot element 997. In some embodiments, when thefirst pivot element 997 is turned in a first rotational direction (e.g.,clockwise), the first tensioning element 994 winds upon the first pivotelement 997, causing the outer sleeve 951 to move proximally, and whenthe first pivot element 997 is turned in a second rotational directionopposite the first rotational direction (e.g., counter-clockwise) thefirst tensioning element 994 unwinds from the first pivot element 997,allowing the outer sleeve 951 to move, distally, in accordance with thebiasing force exerted by the first biasing member 983 onto the outersleeve 951. First tensioning element 994 may be formed from a materialthat is substantially transparent or semi-transparent to radiofrequency(RF) energy, e.g., TEFLON®, or any rigid dielectric material.

Gap adjustment member 940 according to various embodiments includes anaxially slideable, outer-conductor sleeve element 970 having a proximalsleeve portion 971 disposed around a distal portion 965 of the outerconductor 960, and a second biasing member 981 adapted to exert abiasing force against the proximal sleeve portion 971. Second biasingmember 981 may be any suitable biasing member, e.g., a spring. In someembodiments, the second biasing member 981 is adapted to exert a biasingforce sufficient to cause the outer-conductor sleeve element 970 tomove, distally, a length “L13”. In some embodiments, the distance “L13”is about 1 cm.

Outer-conductor sleeve element 970 according to various embodiments maybe operably associated with a second tensioning element 92, e.g., acable, coupled to a second pivot element 995, e.g., a pin and spoolmechanism. In some embodiments, the gap adjustment member 940 can bepositioned, e.g., in relation to the distal end of the outer conductor960, by rotating the second pivot element 995. In some embodiments, whenthe second pivot element 995 is turned in a first rotational direction(e.g., clockwise), the second tensioning element 92 winds upon thesecond pivot element 995, causing the outer-conductor sleeve element 970to move proximally, and when the second pivot element 995 is turned in asecond rotational direction opposite the first rotational direction(e.g., counter-clockwise) the second tensioning element 92 unwinds fromthe second pivot element 995, allowing the outer-conductor sleeveelement 970 to move, distally, in accordance with the biasing forceexerted by the second biasing member 981 onto the outer-conductor sleeveelement 970. Second tensioning element 92 may be formed from a materialthat is substantially transparent or semi-transparent to RF energy,e.g., TEFLON®, or any rigid dielectric material.

Ablation device 901 according to embodiments of the present disclosuremay include a first actuator (e.g., 1197 shown in FIG. 13) operablycoupled to the first pivot element 997 for controlling the lengthadjustment member 950 in an automatic process. In some embodiments, thefirst actuator is operably associated with a controller (e.g., processor82 of the electrosurgical system 1000). Ablation device 901 mayadditionally, or alternatively, include a second actuator (e.g., 1195shown in FIG. 13) operably coupled to the second pivot element 995 forcontrolling the gap adjustment member 940 in an automatic process.

As shown in FIG. 12, the ablation device 901 may include a firstoperating element 1297, e.g. a knob or button, operably coupled to thefirst pivot element 997. In some embodiments, the first operatingelement 1297 (hereinafter referred to as first knob 1297) allows a userto manually adjust the length adjustment member 950 by turning the firstknob 1297 in a first rotational direction (e.g., clockwise), which maywind the first tensioning element 994 upon the first pivot element 997,e.g., causing the outer sleeve 951 to move proximally, and/or by turningthe first knob 1297 in a second rotational direction (e.g.,counter-clockwise), which may unwind the first tensioning element 994from the second pivot element 995, e.g., allowing the outer sleeve 951to move distally. First knob 1297 may have a variety of shapes, texturesand colors. In some embodiments, the first knob 1297 has a substantiallycylindrical shape.

Ablation device 901 may additionally, or alternatively, include a secondoperating element 1295, e.g. a knob or button, operably coupled to thesecond pivot element 995. In some embodiments, the second operatingelement 1295 (hereinafter referred to as second knob 1295) may allow auser to manually adjust the gap adjustment member 940 by turning thesecond knob 1295 in a first rotational direction (e.g., clockwise),which may wind the second tensioning element 92 upon the second pivotelement 995, e.g., causing the outer-conductor sleeve element 970 tomove proximally, and/or by turning the second knob 1295 in a secondrotational direction (e.g., counter-clockwise), which may unwind thesecond tensioning element 92 from the from the second pivot element 995,e.g., allowing the outer-conductor sleeve element 970 to move distally.The shape and size of the first knob 1297 and the second knob 1295 maybe varied from the configuration depicted in FIG. 12.

FIG. 13 shows an electrosurgical system 1100 according to an embodimentof the present disclosure including an ablation device or probe 1101having a radiating section 905. Probe 1101 includes a radiation fieldadjustment member (e.g., length adjustment member 950 and/or gapadjustment member 940 shown in FIG. 11) adapted to allow for selectiveadjustment of the ablation field radiated about the radiating sectioninto tissue. Probe 1101 according to various embodiments is similar tothe probe 901 of FIG. 11, except for a first actuator 1197 and a secondactuator 1195. In some embodiments, the first actuator 1197 is operablycoupled to a first pivot element 997 (shown in FIG. 11), and/or thesecond actuator 1195 is operably coupled to a second pivot element 995(shown in FIG. 11). In some embodiments, the first actuator 1197 and/orthe second actuator 1195 may be electrically coupled to a generatorassembly 1128. First actuator 1197 and the second actuator 1195 mayallow for automatic adjustment of a length adjustment member 950 (shownin FIG. 11) and a gap adjustment member 940 (shown in FIG. 11),respectively, e.g., in connection with a process running on a processor82 (shown in FIG. 10).

Generator assembly 1128 according to various embodiments is configuredto enable a user, via a user interface 25 (shown in FIG. 9) and/or adisplay 21 (shown in FIG. 9), to view at least one ablation patternand/or other energy applicator data corresponding to the probe 1101.Generator assembly 1128 is generally similar to the generator assembly28 of FIGS. 9 and 10, and further description thereof is omitted in theinterests of brevity.

In some embodiments, a surgeon may input via the user interface 25 aselected power output, and the electrosurgical system 1100 controls theactuator 1197 to automatically adjust the length adjustment member 950,to adjust the length of the distal radiating section 905, based on thepower level and/or level of reflected power. As cooperatively shown inFIGS. 11 and 13, the presently disclosed electrosurgical system 1100 maycontrol the actuator 1197 to turn the first pivot element 997 in a firstrotational direction, wherein the first tensioning element 994 may windupon the first pivot element 997, causing the outer sleeve 951 of thelength adjustment member 950 to move proximally, and/or turn the firstpivot element 997 in a second rotational direction, wherein the firsttensioning element 994 may unwind from the first pivot element 997,allowing the outer sleeve 951 to move distally, in accordance with thebiasing force exerted by the first biasing member 983 onto the outersleeve 951.

Electrosurgical system 1100 may additionally, or alternatively, beadapted to control the second actuator 1195 to automatically adjust thegap adjustment member 940, to shorten or lengthen the gap distance ofthe feed point. As cooperatively shown in FIGS. 11 and 13, the presentlydisclosed electrosurgical system 1100 may control the actuator 1195 toturn the second pivot element 995 in a first rotational direction,wherein the second tensioning element 92 may wind upon the second pivotelement 995, causing the outer-conductor sleeve element 970 to moveproximally, and/or turn the second pivot element 995 in a secondrotational direction, wherein the second tensioning element 92 mayunwind from the second pivot element 995, allowing the outer-conductorsleeve element 970 to move distally, e.g., in accordance with thebiasing force exerted by the second biasing member 981 onto theouter-conductor sleeve element 970.

First actuator 1197 and/or the second actuator 1195 may include apneumatic actuator, a hydraulic actuator, an electric actuator, or othersuitable actuator. In some embodiments, the first actuator 1197 is arotary electric actuator. In some embodiments, the second actuator 1195is a rotary electric actuator.

Hereinafter, a method of directing energy to tissue, in accordance withthe present disclosure, is described with reference to FIG. 14, and amethod of adjusting an ablation field radiating into tissue is describedwith reference to FIG. 15. It is to be understood that the steps of themethods provided herein may be performed in combination and in adifferent order than presented herein without departing from the scopeof the disclosure.

FIG. 14 is a flowchart illustrating a method of directing energy totissue according to an embodiment of the present disclosure. In step1410, an energy applicator (e.g., 100 shown in FIG. 1) is provided. Theenergy applicator includes a radiating section (e.g., 150 shown in FIG.2A) having a length (e.g., “L1” shown in FIG. 2A). The radiating sectionincludes an inner conductor (e.g., 210 shown in FIGS. 2A and 2B) and alength adjustment member (e.g., 250 shown in FIGS. 2A and 2B) that iselectrically coupled to the inner conductor. Inner conductor 210 may beformed from a yieldable or flexible, electrically-conductive material,e.g., titanium. The length adjustment member is adapted to allow fordimensional adjustment of the radiating section, and may include asleeve portion (e.g., 255 shown in FIG. 2A). An insulator sleeve (e.g.,270 shown in FIGS. 2A and 2B) may be disposed around at least a portionof an outer conductor (e.g., 260 shown in FIGS. 2A and 2B) of the energyapplicator. The insulator sleeve may extend distally beyond the distalend of the outer conductor, e.g., to enhance slideability and/orrepositionability of the sleeve portion. In some embodiments, theradiating section is configured for radiating energy in a broadsideradiation pattern.

In step 1420, the energy applicator (e.g., 100 shown in FIG. 1) ispositioned in tissue. The energy applicator may be inserted directlyinto tissue, inserted through a lumen, e.g., a vein, needle, endoscopeor catheter, placed into the body during surgery by a clinician, orpositioned in the body by other suitable methods known in the art. Theenergy applicator may be configured to operate with a directionalradiation pattern.

In step 1430, energy is transmitted from an energy source (e.g., 28shown in FIG. 1) through the radiating section (e.g., 150 shown in FIG.2A) to generate an ablation field radiating about at least a portion ofthe energy applicator into tissue. The energy source may be any suitableelectrosurgical generator for generating an output signal. In someembodiments, the energy source is a microwave energy source, and may beconfigured to provide microwave energy at an operational frequency fromabout 300 MHz to about 10 GHz.

In step 1440, the ablation field is adjusted by using the lengthadjustment member to adjust the length of the radiating section. In someembodiments of the presently disclosed energy applicators, the ablationfield may be adjusted by using a gap adjustment member (e.g., 940 shownin FIG. 11) adapted to allow for selective adjustment of the gapdistance of a feed point (e.g., 935 shown in FIG. 11).

FIG. 15 is a flowchart illustrating a method of adjusting an ablationfield radiating into tissue according to an embodiment of the presentdisclosure. In step 1110, an energy applicator (e.g., 901 shown in FIG.11) is provided. The energy applicator includes a distal radiatingsection (e.g., 905 shown in FIG. 11) having a length. The distalradiating section includes a length adjustment member (e.g., 950 shownin FIG. 11) adapted to allow for selective adjustment of the length ofthe distal radiating section. The length adjustment member is operablyassociated with a first pivot element (e.g., 997 shown in FIG. 11).

In step 1520, the energy applicator (e.g., 901 shown in FIG. 11) ispositioned in tissue. The energy applicator may be positioned in tissueby any suitable method.

In step 1530, energy is transmitted from an energy source (e.g., 28shown in FIG. 1) through the distal radiating section (e.g., 905 shownin FIG. 11) to generate an ablation field radiating into tissue. In someembodiments, the energy source is a microwave energy source, and may beconfigured to provide microwave energy at an operational frequency fromabout 300 MHz to about 10 GHz.

In step 1540, the ablation field radiating into tissue is adjusted byrotating the first pivot element (e.g., 997 shown in FIG. 11) in a firstrotational direction or a second rotational direction to adjust thelength of the radiating section. The first pivot element may be rotatedmanually, e.g., using a first knob (e.g., 1297 shown in FIG. 12), orautomatically, e.g., by an actuator (e.g., 1297 shown in FIG. 13)electrically coupled to a generator assembly (e.g., 1128 shown in FIG.13).

Additionally, the energy applicator (e.g., 901 shown in FIG. 11) mayinclude a gap adjustment member (e.g., 940 shown in FIG. 11) adapted toallow for selective adjustment of the gap distance of a feed point.Optionally, in a step 1550, the ablation field radiating into tissue maybe adjusted by rotating a second pivot element (e.g., 995 shown in FIG.11) to adjust the gap distance of the feed point. The second pivotelement may be rotated manually, e.g., using a second knob (e.g., 1295shown in FIG. 12), or automatically, e.g., by an actuator (e.g., 1295shown in FIG. 13) electrically coupled to a generator assembly (e.g.,1128 shown in FIG. 13).

The above-described ablation devices including a length adjustmentmember adapted to allow for dimensional adjustment of a radiatingsection and/or a gap adjustment member adapted to allow for selectiveadjustment of the gap distance of a feed point and methods of directingelectromagnetic radiation to tissue according to embodiments of thepresent disclosure may allow clinicians to avoid ablating orunnecessarily heating tissue structures, such as large vessels, healthyorgans or vital membrane barriers, by adjusting the ablation fieldradiating into tissue. The above-described ablation devices may besuitable for use in open surgical, endoscopic (e.g., rigid or flexible),or percutaneous procedures.

The above-described electrosurgical systems may enable a user to viewone or more ablation patterns and/or other energy applicator datacorresponding to an embodiment of an ablation device, which may allowclinicians to predict ablation volume, avoid complications, and/or planfor treatment margins. The above-described electrosurgical systems maybe adapted to automatically adjust the length of the radiating sectionusing an embodiment of the presently disclosed length adjustment membersand/or the gap distance at the feedpoint using an embodiment of thepresently disclosed gap adjustment members.

The above-described ablation devices may be designed to operate at about915 MHz, about 2.45 GHz, or any other applicable frequency. In someembodiments, the presently disclosed ablation devices including a lengthadjustment member adapted to allow for dimensional adjustment of aradiating section and/or a gap adjustment member adapted to allow forselective adjustment of the gap distance of a feed point, andelectrosurgical systems including the same, may be operated at a firstfrequency, e.g., about 915 MHz, wherein the distal radiating section hasa first length, e.g., about 2 cm, and a second frequency, e.g., about2.45 GHz, wherein the distal radiating section is adjusted to have asecond length, e.g., about 1 cm.

The above-described ablation devices with adjustable radiating sectionlengths may be suitable for use in surgical or non-surgical (e.g.,interventional radiology, etc.) settings.

Although embodiments have been described in detail with reference to theaccompanying drawings for the purpose of illustration and description,it is to be understood that the inventive processes and apparatus arenot to be construed as limited thereby. It will be apparent to those ofordinary skill in the art that various modifications to the foregoingembodiments may be made without departing from the scope of thedisclosure.

What is claimed is:
 1. An energy applicator for directing energy to tissue, comprising: a feedline; a radiating section operably coupled to the feedline, the radiating section including a dielectric material and an inner conductor, a portion of the inner conductor extending distally beyond a distal end of the dielectric material, wherein the radiating section has a length; and a length adjustment member adapted to allow for selective adjustment of the length of the radiating section, wherein the length adjustment member includes a tapered portion disposed at a distal end of the radiating section, the tapered portion defining a cavity therein, wherein a distal portion of the portion of the inner conductor extending distally beyond the distal end of the dielectric material includes a coiled portion disposed within the cavity, the cavity configured to allow the coiled portion of the inner conductor to wind or unwind as the length of the radiating section is adjusted.
 2. The energy applicator of claim 1, wherein the length adjustment member includes an inner sleeve and an outer sleeve disposed around at least a portion of the inner sleeve.
 3. The energy applicator of claim 2, wherein the inner sleeve includes a proximal end portion, a distal end portion, and a threaded middle portion disposed between the proximal and distal end portions, and the outer sleeve includes a threaded end portion engaged with the threaded middle portion of the inner sleeve.
 4. The energy applicator of claim 3, wherein the outer sleeve further includes a middle portion and wherein the distal end portion of the inner sleeve includes a mechanical interface configured to engage an inner surface of the middle portion of the outer sleeve.
 5. The energy applicator of claim 3, wherein the outer sleeve further includes a middle portion and a tapered end portion disposed distal to the middle portion.
 6. The energy applicator of claim 3, wherein the inner sleeve is formed of a rigid dielectric material.
 7. The energy applicator of claim 3, wherein the inner sleeve is formed of an electrically-conductive material.
 8. The energy applicator of claim 1, wherein the feedline includes an inner conductor, an outer conductor coaxially disposed around the inner conductor, and a dielectric material disposed therebetween.
 9. The energy applicator of claim 8, wherein a portion of the inner conductor and the dielectric material of the feedline extends beyond the outer conductor at a distal end of the feedline.
 10. The energy applicator of claim 9, wherein the inner conductor is electrically coupled to the length adjustment member.
 11. The energy applicator of claim 1, wherein one or more portions of the inner conductor is formed of a material having elasticity, the one or more portions including the coiled portion of the inner conductor.
 12. An electrosurgical system, comprising: a generator; and an ablation device including: a feedline; a radiating section operably coupled to the feedline, the radiating section including a dielectric material and an inner conductor, a portion of the inner conductor extending distally beyond a distal end of the dielectric material, wherein the radiating section has a length; and a radiation field adjustment member adapted to allow for selective adjustment of the ablation field radiated about the radiating section into tissue, the radiation field adjustment member including a length adjustment member adapted to allow for selective adjustment of the length of the radiating section, wherein the length adjustment member includes a tapered portion disposed at a distal end of the radiating section, the tapered portion defining a cavity therein, wherein a distal portion of the portion of the inner conductor extending distally beyond the distal end of the dielectric material includes a coiled portion disposed within the cavity, the cavity configured to allow the coiled portion of the inner conductor to wind or unwind as the length of the radiating section is adjusted.
 13. The electrosurgical system of claim 12, wherein the length adjustment member includes an inner sleeve and an outer sleeve disposed around at least a portion of the inner sleeve.
 14. The electrosurgical system of claim 13, wherein the inner sleeve includes a proximal end portion, a distal end portion, and a threaded middle portion disposed between the proximal and distal end portions, and the outer sleeve includes a middle portion and a threaded end portion engaged with the threaded middle portion of the inner sleeve.
 15. The electrosurgical system of claim 14, wherein the outer sleeve further includes a middle portion and wherein the distal end portion of the inner sleeve includes a mechanical interface configured to engage an inner surface of the middle portion of the outer sleeve.
 16. The electrosurgical system of claim 14, wherein when the outer sleeve is placed in a proximal-most position, the threaded end portion engages with a proximal portion of the threaded middle portion disposed closest to the proximal end portion of the inner sleeve. 